Question

triangle abc is an isosceles right triangle. what is the measure of one base angle? 30° 45° 60° 90°

Explanation:

Step1: Sum of triangle angles

The total sum of angles in any triangle is $180^\circ$.

Step2: Identify right angle

An isosceles right triangle has one $90^\circ$ angle.

Step3: Calculate remaining angle sum

Subtract the right angle from the total: $180^\circ - 90^\circ = 90^\circ$.

Step4: Split equal base angles

Since the triangle is isosceles, the two base angles are equal. Divide the remaining sum by 2: $\frac{90^\circ}{2} = 45^\circ$.

Answer:

45° (Option: 45°)